Ok the term "config type" doesn't exist anymore :). Now it's "config
section", which is more explicit.
Other changes:
game > game_slug
runner > runner_slug
game_config > game_level
runner_config > runner_level
system > system_level
I sliced through a bigger bunch of changes to create this commit (for
clarity) but couldn't slice in an exactly meaningful way so there are
a couple places that only make sense with the next commit.